System for transferring substrates into clean rooms

ABSTRACT

A system for transferring substrates in a clean room (100) has a box (1) for receiving a cassette (101) that contains the substrates (102), and a bottom (2) that hermetically closes the box (1) and that can be locked and unlocked in the box (1) by a locking mechanism. The locking mechanism has a captive C-washer (25) rotatively mounted in the box bottom (2). The captive C-washer (25) drives locking elements (21a, 21b; 321a, 321b), preferably by means of connecting rods (24a, 24b; 324a, 324b). The locking elements (21a, 21b; 321a, 321b) engage locking slots (11a, 11b) of the box (1). The captive C-washer (25) has catching bores (26a, 26b) engaged by the locking bolts (41a, 41b) of a rotary disk (45) arranged in a lock gate (4). A swivelling movement of the rotary disk (45) driven by a driving device of the system causes the bottom (2) to be locked and unlocked in the box (1). A reception frame (3) allows the box (1) to be accurately positioned and a blocking mechanism blocks the box (1) in the reception frame (3). The blocking mechanism is mechanically coupled to the rotary disk (45), so that when the bottom (2) is locked in the box (1) by a swivelling movement of the captive C-washer (25), the box (1) is unblocked in the frame (3), whereas when the bottom (2) is unlocked from the box (1) by a swivelling movement of the captive C-washer (45), the box (1) is blocked in the reception frame (3).

BACKGROUND OF THE INVENTION

The present invention relates to a system for transferring substratesinto a clean room, having a box for receiving a cassette containing thesubstrates, with a box bottom which hermetically seals the box and whichcan be locked into and unlocked from the box by means of a lockingmechanism. The locking mechanism has a pivot disk rotatably seated inthe box bottom which, preferably by means of push rods, drives lockingelements which engage locking slots in the box pivot disk has engagementbores which are engaged by locking pin of a turntable disposed in a lockgate and which, driven by an operating device of the system, perform apivot movement triggering the locking and unlocking of the box bottom inthe box, having a receiving frame for the positionally correctorientation of the box and a detent mechanism for fixing in place of thebox in the receiving frame.

Such a system--identified by the technical term "Standard MechanicalInterface (SMIF)"--is known from U.S. Pat. No. 4,995,430. The seriousdisadvantage of this system is that the locking mechanism and the detentmechanism are embodied to be completely separated from each other. Thishas the disadvantageous result that it becomes necessary to providecomplex electronic monitoring and control devices which are intended toassure that, on the one hand, locking of the box bottom in the box isonly terminated once the box has been fixed in place in the receivingframe and, on the other hand, that the box bottom is locked in the boxbefore the fixing in place of the box in the receiving frame is removed.

A further disadvantage of the known system resides in that here theoperating device for locking and unlocking of the box bottom in the boxby means of the turntable normally provided for this is disposedunderneath the lock gate. This has the disadvantageous result that theknown system cannot be integrated into clean room installations.Instead, the SMIF must be docked to the clean room installation. Aseparate lifting device is then required for lowering the lock gate.Furthermore, a separate transporting device is required, whichtransports the substrate cassette of the known system from the loweredlock gate to a lifting device of the clean room installation from wherethe further manipulation of the cassette with the substrates containedtherein is performed. The separate lifting device required with theknown SMIF systems and the transport device moving the substratecassette from the lifting device of the SMIF to the lifting device ofthe clean room makes the construction of the known SMIF system moreexpensive and complicated in a disadvantageous way.

A further disadvantage rests in the complicated design of the lockingmechanism. To achieve the tilting movement of the locking elements atthe end of the locking process of the box bottom in the box, it isprovided that the pins by means of which the push rods are linked withthe pivot disk are guided in a cam way of the pivot disk so that bymeans of an elevation of the link point of the push rods a tiltingmovement of the locking elements is achieved. Such a structural solutionis not only complicated and therefore expensive for producing the pivotdisk along with the cam ways, it also disadvantageously increases thestructural height of the box bottom. In addition, such a constructionentails excessive wear of the pins and the cam way because of theincreased material stresses thereon occurring in the course of thetilting of the locking elements.

A further disadvantage of the known system lies in its lack ofconsideration of the technical air requirements necessary in clean roominstallations to prevent the contamination of the highly sensitivesubstrates. No devices are provided in the known system which keep awayairborne particulates which possibly have penetrated into the cleanroom. In this case this disadvantage of the known system hasparticularly serious effects because the lifting device itself, which isdisposed in the clean room and which lowers the lock gate, brings suchairborne particulates into the clean room: abrasion particles aregenerated around the lifting device which are subject to friction andwhich in the known system reach the portion of the clean room receivingthe substrates in a disadvantageous manner.

SUMMARY OF THE INVENTION

It is the object of the present invention to further develop a system ofthe type mentioned at the outset in such a way that the above describeddisadvantages are avoided.

This object is attained in that the detent mechanism is mechanicallyconnected with the turntable in such a way that a pivot movement of theturntable, which triggers locking of the box bottom in the box, causesthe termination of the fixing in place of the box in the receivingframe, and that a pivot movement of the turntable, which triggerstermination of the locking of the box bottom in the box causes fixing inplace of the box in the receiving frame.

By means of the measures in accordance with the present invention aforced locking of the box bottom in the box and of the box in thereceiving frame is achieved in a particularly advantageous manner. Thus,an elaborate electronic monitoring and control device is no longerrequired to assure, on the one hand, that the box bottom is not unlockeduntil the box is fixed in place in the receiving frame or, on the otherhand, the fixing in place of the box in the receiving frame is notterminated without the box bottom first having been fixed in place inthe box. Thus, the measures proposed in accordance with the presentinvention advantageously effect the assured and dependable prevention ofcontamination of the substrates.

An advantageous development of the present invention provides that thecoupling of the detent mechanism and the locking mechanism take place insuch a way that a cam plate is rigidly connected with the turntable ofthe lock bottom. The cam plate has control cams in each of which a boltis guided and is connected with a further push rod. The rotary motion ofthe turntable is translated into a linear displacement motion of thefurther push rods, by means of which the pivot movement of a detentelement acting on shoulders of the box in the latter can be controlled.Such a mechanical linkage of the locking and unlocking of the box bottomin the box with the fixing in place of the box in the receiving frame isdistinguished particularly advantageously by its structural simplicity.

A further advantageous development provides that the control of thepivot movement of the detent elements takes place by means of thecontrol cams of the cam plate, which have a constant radius over a firstarea and an increasing radius in a following second area. When the boltsconnected with the further push rods travel through this second area ofthe control cams of the cam plate, the increasing radius of the controlcams in an advantageous manner causes a linear displacement movement ofthe further push rods, which then act upon a pivot lever which isconnected via a bolt with a detent element. Because of this the detentelement is moved against the spring force of a pivot spring out of itsdetent position into its receiving position in the receiving frame. Thistype of control of the detent elements has the advantage--besides itsconstructive simplicity--that only a few mechanical parts are needed forthe assured and dependable triggering and control of the pivot movementof the detent elements, because of which such a detent mechanism can bemanufactured particularly simply and inexpensively.

A further advantageous development of the present invention providesthat the operating device driving the detent mechanism as well as thelocking mechanism is completely disposed in the interior chamber of thelock gate. This feature has the advantage that the system in accordancewith the present invention can be integrated particularly simply intoclean room installations. By means of it it is possible for the liftingdevice of the clean room to act directly on the lock gate. Thus, withthe system of the present invention lowering of the lock gate togetherwith the box bottom and the substrate cassette placed thereon isperformed by the lifting device of the clean room. It therefore is nolonger required--as in the known installation--to dock the system to theclean room and to provide a separate lifting device for lowering thelock gate as well as a separate transport device for transporting thecassette from the lifting device of the system to the lifting device ofthe clean room. Thus, in an advantageous manner these measures of thepresent invention achieve for one thing an increase in the employmentrange of the system of the present invention in relation to knownsystems, because the system of the present invention can be integratedinto clean room installations. For another thing, a separate liftingdevice and a separate transport device are no longer advantageous,because of which the manufacturing costs of such clean roominstallations can be considerably reduced.

In a particularly advantageous manner the operating device, which iscompletely disposed in the interior of the lock gate, is formed by abracket, which is hingedly seated in a pivot point, a motor received inthe bracket, on the motor shaft of which a threaded spindle is flangedwhich meshes with a counter-screw thread of a fork which, via a secondhinge point, connects the cam plate which is rigidly connected with theturntable of the lock gate. This construction in accordance with thepresent invention of the operating device of the system of the presentinvention is not only distinguished by its structurally simple designbut also by its compactness, because of which the disposition of theoperating device in the interior of the lock gate can be uncomplicatedand especially simple in a particularly advantageous manner.

A further advantageous development of the present invention representsan alternative embodiment of the above described common operating devicefor the detent and locking mechanism. It is provided here that thisoperating device has a gear motor, on the motor shaft of which a wormhas been flanged. This engages a worm wheel fixedly connected with apinion. In turn, the pinion is in engagement with the cam plate embodiedas a spur wheel. It is advantageously achieved by these measures thatthe gear motor can be installed horizontally in the lock gate, theresult of which is an advantageous particularly compact construction ofthe operating device of the present invention and thus a space-savingembodiment of the lock gate receiving this operating device.

A further advantageous development of the present invention providesthat the locking element of the locking mechanism has at least onerunner which slides on the underside of a housing of the box bottom andcooperates with a stop on the housing. This stop limits the lineardisplacement movement of the locking element, triggered by the push rod,in the direction of an associated locking slot of the box and--withfurther movement of the push rods--provides, in a particularlyadvantageous manner, that the tilting of the locking element can beachieved in a particularly simple and material-protecting manner. It isfurthermore provided by the present invention that the push rods, whichare each rotatably fastened on the pivot disk of the box bottom via alink, are moved beyond dead center of the links in the course of thepivot movement causing locking of the box bottom. By means of thismeasure it is achieved in an advantageous manner that locking of the boxbottom in the box is assuredly and dependably safe from automaticopening.

A further advantageous development represents an alternative embodimentof the above described locking mechanism. It is provided in accordancewith the present invention that the locking element of the lockingmechanism has at least one slider which is displaceably guided in aguide element. A rotatably seated bar is linked with the slider, whichtranslates the linear displacement movement of the locking element inthe direction of the associated locking slot of the box, triggered bythe push rod which preferably is in the form of a toggle lever, into arotating movement of its end, which preferably is embodied as a beak, bymeans of which the box bottom is assuredly and dependably locked in thebox. An extremely strong locking force between the box and the boxbottom is created in an advantageous manner by these measures of thepresent invention, which results in a particularly large force effect ona seal disposed between the box and the box bottom.

A further advantageous development of the present invention providesthat a ventilating device for the clean room is provided, by means ofwhich a clean air flow which flows around the substrates is fed into theclean room. The technical air requirements of such a clean roominstallation are met by means of the ventilating device for the cleanroom provided by the present invention. In an advantageous manner theclean air flow supplied provides rinsing of the substrates. Thedisplacement flow caused by the clean air flow prevents the inflow ofcontaminated air to the very delicate substrates, so that theircontamination by airborne particulates possibly present in the cleanroom is prevented. The direction of the clean air flow is advantageouslyselected to be parallel to the surface of in flowing substrates, so thata turbulence-free course of the clean air flow in the clean room isassured.

An advantageous development of the present invention provides that agrid element is provided in the clean room which in a particularlyadvantageous manner causes the steadying of the clean air flow flowingthrough the clean room. In this case the grid element is preferablydisposed in front--viewed in the flow direction of the clean airflow--of a lifting device integrated into the clean room. By thisdisposition in accordance with the present invention it is achieved inan advantageous manner that the grid element, in addition to its airguidance functions, also provides a mechanical screen of the part of theclean room which contains the lifting device, so that abrasion particlesgenerated in the course of a lifting movement of the lifting devicecannot directly come into the part of the clean room containing thesubstrates.

A further advantageous development of the present invention providesthat after flowing through the part of the clean room containing thesubstrates, the clean air flow is guided to the lifting deviceintegrated into the clean room. By means of the washing of the liftingdevice by the clean air flow provided in accordance with the presentinvention, abrasion particles being created on the parts of the liftingdevice subjected to friction are kept away from the part of the cleanroom containing the substrates and are moved away in an advantageousmanner by the clean air flow and in this way removed from the cleanroom. A definite increase in meeting the technical air requirements ofsuch a clean room installation is achieved by this measure of thepresent invention.

A further advantageous development of the present invention providesthat a substrate fastening device is disposed in the box, which has ascissors brace cooperating with the box bottom, by means of which alifting motion of the box bottom is translated into a pressing movementof a pressure strip connected with the scissors brace against thesubstrate received in the cassette. An assured fixed seating of thesubstrate in the cassette during a removal or transport operation isachieved by this measure of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details of the present invention can be taken from the exemplaryembodiments which will be described below in connection with thedrawings. Shown are:

FIG. 1, which is a section through a first exemplary embodiment,

FIG. 2, which is an exploded view of FIG. 1,

FIG. 3, which is a section through a box bottom of the first exemplaryembodiment,

FIG. 4, which is a section through the box bottom along the line IV--IVof FIG. 2,

FIG. 5, which is a section through a receiving frame of the firstexemplary embodiment,

FIG. 6, which is a top view of the receiving frame from the direction VIof FIG. 2,

FIGS. 7 and 8, which show parts of the detent device of the exemplaryembodiment,

FIG. 9, which is a bottom view of a lock gate without the bottom plateof the first exemplary embodiment,

FIGS. 10 and 11, which show a section through a second exemplaryembodiment,

FIG. 12, which is a section through the second exemplary embodimentalong the line XII--XII of FIG. 10,

FIG. 13, which is a section through a box bottom of the second exemplaryembodiment,

FIG. 14, which is a section through the box bottom along the lineXIX-XIV of FIG. 13,

FIG. 15, which shows a detail Y of FIG. 10 without a cassette on anenlarged scale and corresponding to a section along XV--XV of FIG. 14,

FIG. 16, which is a bottom view of a lock gate without the bottom plateof the second exemplary embodiment, and

FIG. 17, which is a section through the detail X of FIG. 16 along theline XVII--XVII of this figure on an enlarged scale.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The first exemplary embodiment of a system for transferring substratesinto clean rooms represented in FIGS. 1 and 2 has a box 1, a box bottom2, a receiving frame 3 and a lock gate 4. The space enclosed by the box1 and the box bottom 2 is used in a known manner for receiving acassette with substrates, not represented in FIGS. 1 and 2, which areintended to be conveyed to a clean room, not shown, located below thelock gate 4.

In its lower area 10 adjoining the lateral surfaces 2' of the box bottom2, the box 1 has two locking slots 11a, 11b, which are respectivelyengaged by a locking element 21a, 21b of the locking mechanism of thebox bottom 2. Reference is made in this connection to FIGS. 3 and 4,wherein respectively only the left half of the symmetrically constructedlocking mechanism is shown. The locking mechanism, disposed in a hollowchamber 2a enclosed by a housing 22 of the box bottom 2, has a pivotdisk 25 which is rotatable around a peg 27 of the housing. One end of apush rod 24a, 24b is linked, respectively, via one joint 212a, 212b onthe top of the pivot disk 25 (as shown in FIG. 4), the other end of thepush rod 24a, 24b is connected, respectively via another joint 210a,210b with the locking element 21a, 21b embodied as a bar. Each lockingelement 21a and 21b has respectively two runners 29a and 29b, which aredisposed on the back end of the locking element 21a, 21b associated withthe pivot disk 25 and which slide on the underside 23 of the housing 22of the box bottom 2. Respectively one pressure spring 211 (see FIG. 3)acts on a depression disposed in the rear area of the locking element21a, 21b and is supported on the associated push rod 24a, 24b andprevents the locking element 21a, 21b from pitching down on theunderside 23 of the housing 22 in the course of its displacement move,which is triggered by the rotating movement of the pivot disk 25 andtransmitted by the push rods 24a, 24b. In addition, the housing 22 hasrespectively two stops 28a, 28b, which cooperate with the runners 29a,29b of each locking element 21a, 21b and which limit the lineardisplacement movement of the locking elements 21a, 21b, guided by guideelements 20 (FIG. 4) of the housing 22, in the direction of the lockingslots 11a, 11b.

The described manner of operating the locking elements 21a, 21b by meansof the push rods 24a, 24b is not the only possible type of construction.Instead, on the basis of the above description, one skilled in the artcan determine which alternatives he can employ to translate the movementof the pivot disk 25 into a locking and unlocking movement of thelocking elements 21a, 21b. Reference is made by way of example to thedescription hereinafter of a second exemplary embodiment, and inparticular to FIGS. 15 and 16.

Locking of the box bottom 2 in the box 1 is performed as follows: whenthe pivot disk 25 is pivoted in the direction of the arrow P (FIG. 4),the push rods 24a, 24b move the locking elements 21a, 21b associatedtherewith outwardly. The latter first performs a linear movement and inthe process engages the locking slots 11a, 11b of the box 1. As soon asthe runners 29a and 29b push against the stops 28a and 28b, the lockingelements 21a, 21b are tilted. Clamping between the box 1 and a seal 214extending around the entire circumference of the box bottom 2 is causedby means of this, wherein a particularly strong force effect on the seal214 of the box bottom 2 is achieved in an advantageous manner because ofthe toggle lever effect of the push rods 24a, 24b occurring as a resultof the tilting of the locking elements 21a, 21b. Therefore the seal isparticularly strongly pushed against the box 1. Because of this,hermetic sealing of the space bordered by the box 1 and the box bottom 2locked in it becomes possible without danger to transporting of thecassette contained in it together with the substrate throughcontaminated rooms.

It is provided in a particularly advantageous manner that in the courseof the pivot movement of the pivot disk 25 the push rods 24a, 24b aremoved beyond dead center of the joints 212a, 212b. Self-locking of theclosing mechanism is achieved by means of this tripping, so that lockingof the box bottom 2 in the box 1 is securely and dependably safe fromautomatically opening.

The underside 23 of the housing 22 has an opening 23', so that thelocking pins 41a, 41b of a turntable 45 of the lock gate 4 disposedbeneath the box bottom 2 can enter the engagement bores 26a, 26bprovided on the underside of the pivot disk 25. In addition, there areseveral, preferably three, alignment bores 209a, 209b (see FIG. 2) inthe underside 23 of the housing 22 of the box bottom 2, which acttogether with associated alignment projections 409a, 409b (see FIG. 2)of the lock gate 4 and which, together with the receiving frame 3, takecare of a positionally exact orientation of the box bottom 2 and the box1.

Detent elements 31a and 31b are used for fixing the box 1 in place inthe receiving frame 3 and act on a radially outwardly directed shoulder12a and 12b of the box 1 (see FIG. 2). The detent elements 31a, 31b arecomponents of a symmetrically constructed detent mechanism, the lefthalf of which is shown in detail in FIGS. 5 to 8--to which reference ismade--. Two cutouts 39 (see FIGS. 6 and 8) are disposed in the receivingframe 3, which permit a backward pivoting of the detent elements 31a,31b from the locking position shown in FIGS. 1 and 2 into a receivingposition in which they are positioned in the interior of the receivingframe 3 and therefore make possible the easy insertion of the box 1 intothe receiving frame 3. Each detent element 31a, 31b is placed on a bolt35a, 35b--as can be best seen in FIG. 7--, which respectively has apivot lever 32a, 32b on its lower end (FIGS. 1, 2 and 5) whichcooperates with respectively one further push rod 44a, 44b extending outof the inner chamber 4' of the lock gate 4. Action on the pivot levers32a, 32b by the further push rods 44a, 44b guided in guides 48a, 48b ofthe lock gate 4 results in the detent elements 31a, 31b being pivoted,through slots 310 of the receiving frame 3 into their receiving positionin cutouts 39 of the receiving frame 3 against the spring force ofrespectively one pivot spring 37 (FIG. 7), coaxially disposed withrespect to the bolt 35a, 35b, out of their detent position, in whichthey act on the shoulders 12a, 12b of the box 1 and lock them in thisway in the receiving frame (3).

In this connection it has been provided that a first end of each pivotspring 37 acts on a radially inward extending projection 38 of thedetent elements 31a, 31b, which is simultaneously used as a stop and issupported on the housing 33 of the receiving frame 3 and in this waylimits the pivot angle of the detent elements 31a, 31b (FIG. 8). Asecond end of the pivot spring is supported on the receiving frame 3.

The further push rods 44a, 44b are provided on their ends facing awayfrom the pivot levers 32a, 32b with respectively one fork 49a, 49b--ascan best be seen from FIGS. 1, 2 and 9--, which via respectively onebolt 50a, 50b engage control cams 51a, 51b of a cam plate 43, fixedlyconnected with the turntable 45. Reference is made in this connection toFIGS. 2 or 9. In this case the control cams 51a, 51b of the cam plate 43are designed in such a way that they have a constant radius in a firstarea 51a', 51b'. This radius is of such a dimension that the furtherpush rods 44a, 44b do not act on the pivot levers 32a, 32bor--preferably--have retreated into the inner chamber 4' of the lockgate 4 when the bolts 50a, 50b move in the first area 51a', 51b' of thecontrol cams 51a, 51b of the cam plate 43.

In a second area 51a", 51b" adjoining this first area 51a', 51b', theradius of the control cams 51a, 51b increases, so that with a continuedpivoting movement of the cam plate 43 in the direction of the arrow Pthe further push rods 44a, 44b, which are connected via the bolts 51a,51b with the cam plate 43, are radially displaced outwardly and act onthe pivot levers 32a, 32b. The pivot movement of the pivot levers 32a,32b triggered by this movement is transmitted via the bolts 35a, 35b tothe detent elements 31a, 31b, as a result of which they retreat from theshoulders 12a, 12b of the box 1 into the cutouts 39a, 39b of thereceiving frame 3 and in this way release the box 1.

This pivot movement of the cam plate 43 is effected by the operatingdevice represented in FIG. 9, which is disposed in a particularlyadvantageous manner in the inner chamber 4' of the lock gate 4. Thismeasure has, as a result, the fact that the lifting device 5 (FIG. 1) ofthe clean room can act directly at the lock gate 4. In this way itbecomes possible to embody the described lock system as an integralcomponent of the clean room. Therefore there is no longer adependence--as in the known systems, to dock it against the clean roomand to provide a separate lifting device for lowering the lock gate 4together with the box bottom 2. An operating device for the detentmechanism disposed outside of the lock gate 4, which therefore isinterfering, is no longer necessary.

The common operating device for the detent and the locking mechanism hasa bracket 56 which is hingedly seated by a pivot pin 57. A motor 58 withattached gear is received in the bracket 56. A threaded spindle 54 isflanged to the motor shaft of the motor 58 and meshes with acounter-screw thread of a fork 53. The fork 53 connects the cam plate 43via a second hinge pin 52.

Summarizing the structural design of the described system it should bestated that the dimensioning and the particular sizes of this "StandardMechanical Interface" are recited in Document No. 1872 of the SEMIStandard (Semiconductor Equipment and Materials International). Explicitreference to this document is therefore made. For one skilled in theart, the measurements not contained therein inevitably result from theabove description, so that their explicit listing can be omitted here.

The functional progress during transferring a cassette filled withsubstrates and contained hermetically sealed in the box 1 is as follows:

In the locked position of the system for transferring substrates toclean rooms, the lock gate 4 is firmly pressed against the cover frame36 of the receiving frame 3 by the lifting device 5 of the clean roominstallation, so that the clean room located under the lock gate 4 ishermetically sealed. The further push rods 44a, 44b of the lock gate 4are extended and act on the pivot levers 32a, 32b of the detentmechanism for the box 1. The detent elements 31a, 31b, connected withthe pivot levers 32a, 32b via the bolts 35a, 35b, have retreated intothe cutouts 39a, 39b of the receiving frame 3, so that the box 1,together with the box bottom 2, which is locked into it by means of thelocking elements 21a, 21b, can be seated into the receiving frame 3. Thelocking pins 41a, 41b of the turntable 45 of the lock gate 4 are intheir receiving position, so that they can enter into the engagementbores 26a, 26b of the pivot disk 25 of the box bottom 2 when the box 1is inserted.

After the box has been placed, the motor 58 received in the bracket 56is activated and places the cam plate 43 in motion in the direction ofthe arrow P (FIG. 9) via the threaded spindle 54 and the counter-screwthread provided in the fork 53. The bolts 50a, 50b are moved along thesecond curve areas 51a", 51b" of the control cams 51a, 51b in thedirection of the first curve areas 51a', 51b' by means of this pivotmovement of the cam plate 43. As a result the push rods 44a, 44b areretracted. The spring force of the pivot springs 37 pushes the detentelements 31a, 31b through the slots 310 of the receiving frame 3 out oftheir receiving position into their detent position, so that they act onthe outwardly protruding shoulders 12a, 12b of the box 1 and in this waylock the box 1 in the receiving frame.

The pivot movement of the cam plate 43 is transmitted via the lockingpins 41a, 41b of the turntable 45, which is fixedly connected with thecam plate 43, to the pivot disk 25. This causes the push rods 24a, 24bto retreat, as a result of which the locking elements 21a, 21b of thebox bottom 2 are retracted and retreat into the interior of the housing22 of the box bottom 2. The locking of the box bottom 2 to the box 1,which is now firmly maintained in the receiving frame 3 by the detentelements 31a, 31b, is terminated by this and the box bottom 2 isreleased.

The lock gate 4 together with the box bottom 2 and the substratecassette placed on it are then lowered into the clean room with the aidof the lifting device 5.

In the opposite direction of the functional progress, the pivot movementof the cam plate 43 in the opposite direction (opposite the direction ofthe arrow P) is first translated by the locking pins 41a, 41b into apivot movement of the turntable 25, as a results of which the push rods24a, 24b move the locking elements 21a, 21b outward in the directiontoward the locking slots 11a, 11b of the box 1 until they finally enterthe locking slots 11a, 11b and--as already described above--seal the boxbottom 2 hermetically in the box 1. By means of a further pivot movementof the cam plate 43, the further push rods 44a, 44b come out of thehousing of the lock gate 4, act on the pivot levers 32a, 32b, as aresult of which the detent elements 31a, 31b recede through the slots310a, 310b of the receiving frame into the cutouts 39a, 39b of thelatter against the displacement force of the pivot springs 37. The box1, together with the box bottom 2 locked together with it is now nolonger locked in the receiving frame 3. Therefore it can be easily takenout of the lock area formed by the receiving frame 3 and the lock gate4.

The second exemplary embodiment shown in FIGS. 10 and 11 agrees to alarge extent with the above described first exemplary embodiment, sothat the same reference numerals can be used for like parts. For thepurpose of a short and precise description of the second exemplaryembodiment the parts and elements which had already been extensivelydescribed in the first exemplary embodiment will therefore not bedescribed again in what follows.

The immediately noticeable difference between FIG. 1 and FIGS. 10 and 11consists in that the clean room 100 situated underneath the lock gate 4,which had not been illustrated in FIG. 1 and had only been described inwords in the explanation of the first exemplary embodiment, is nowexplicitly shown in these drawing figures. Furthermore, a cassette 101with substrates 2 is shown in FIGS. 10 and 11, wherein the cassette 101is shown in its received position in FIG. 10, and in its position whereit is lowered into the clean room 100 in FIG. 11.

One difference between the first and second exemplary embodiments of asystem for transferring substrates into clean rooms lies in a scissorsbrace 105 fastened on the side of the box 1, which fixes the substrates102 in the cassette 101 by means of a pressure strip 106. This isaccomplished in that in the closed state of the system the pressurestrip 106 of the scissors brace 105 is pushed upward by the box bottom2. In the course of this the scissors brace 105 opens and pushes thepressure strip 106 against the substrates 102 and in this way causesthem to be fixed in place in the cassette 101. With the box bottom 2lowered, the scissors brace 105 with the pressure strip 106 comes torest against the wall 1' of the box 1 because of its own weight andreleases the cassette 101, so that it can be easily inserted into theclean room 100 (FIG. 11).

A substrate fixing device of the box 1 is formed by the scissors brace105 and the pressure strip 106 which assures in an advantageous mannerthe fixing in place of the substrates 102 in their cassette 101.Therefore the box 1 together with the cassette contained in it and thesubstrates 102, can be taken from the receiving frame 3 and transportedwithout having to fear that the substrates 102 will fall out of thecassette 101 because of vibrations or jarring occurring during theremoval or transport operation. Thus a simple manipulation of the box 1during its removal from the receiving frame 3 or during transport isassured, because even a non-horizontal removal or transport position ofthe box 1 cannot result in damage to the substrates 102.

The lifting device 5 integrated into the clean room 100 (also see FIG.12) has a threaded spindle 163 driven by an electric motor, by means ofwhich a carriage 162 can be moved up and down along a guide rail 166. Asbest seen in FIG. 12, the drive of the threaded spindle 163 is providedby a drive motor 169 which provides the lifting movement of the carriage162 extending in the direction of the arrow Z via a belt 168 and pulleys167a, 167b. A support arm 164 fastened on the carriage 162 supports thelock gate 4 via leveling bolts 165a, 165b.

It is now important that a ventilating device 200 is integrated into theclean room 100. For this purpose a lateral wall 100' of the clean room100 has an opening 201 through which clean air can be supplied to theclean room 100. The clean air flowing into the clean room 100 isidentified by arrows RL in FIGS. 10 to 12. The supplied clean air RLflows through the clean room 100 and penetrates through a perforatedplate 203, which encapsulates the mechanical parts and the drive of thelifting device integrated into the clean room 100, and is guided via anopening 205 in the housing bottom 204 of the clean room 100 into aventilator housing 220 of the system, in which a ventilating unit 222 isdisposed.

By means of this supply of clean air RL to the clean room 100 thetechnical air requirements of such a system for transferring substratesinto clean rooms are met in an advantageous manner: the clean air RL,which preferably flows in parallel with the substrates 102, provides inan advantageous manner a washing of the substrates 201 contained in thecassette 101 and prevents air which is contaminated with airborneparticulates possibly present in the clean room 100 from reaching thesubstrates 102 contained in the cassette 101. Thus the supplied cleanair RL forms a displacement flow which keeps airborne particulates awayfrom the substrates 102. In the course of this the perforated plate 203of the clean room 100 provides an even aspiration--i.e. a steadying ofthe clean air flow--of the clean air RL through the openings 201 of theclean room 100 and in addition assures an even removal of the clean airRL through the opening 205 of the bottom 204 of the clean room 100 intothe ventilator housing 220.

In this connection it is advantageous that the ventilating unit 222 iscontrollable, so that the speed of the displacement flow created by theclean air RL, which causes washing of the substrate 102, can be adaptedto the respective external requirements--essentially the pressuregradient between in flowing and outflowing air--. By means of this it isassured that the ventilation device 200 of the described system can beadapted to individual requirements of the users.

The perforated sheet 203 provided in the clean room 100 furthermoreprovides--in addition to taking care of the even flow of clean air RL inthe clean room 100--that abrasion particles created on the parts of thelifting device 5 subjected to friction can no longer directly reach thesection 100a of the clean room 100 which contains the cassette 101filled with substrates 102. Such a danger of contamination of the cleanroom section 100a by abrasion particles is also eliminated by thedescribed routing of the clean air RL: because in addition to thesection 100a of the clean room 100 containing the substrates 102, italso floods the lifting device 5, so that the abrasionparticles--created for example in the course of the movement of thecarriage 162 along the guide rail 166--are immediately removed throughthe opening 205 of the housing bottom 204 of the clean room 100 into theventilator housing 220. Thus the exhaust air, symbolically representedby arrows AL, from the clean room 100 is removed by the ventilating unit222 via the ventilator housing 220.

It is of course easily possible to employ the ventilating device 200 ofthe clean room 100 of the second exemplary embodiment also in the systemfor transferring substrates in accordance with the first exemplaryembodiment.

FIGS. 13 and 14, corresponding to FIGS. 3 and 4 of the first exemplaryembodiment, as well as FIG. 15 illustrate a second embodiment of thelocking mechanism for fixing in place the box bottom 2 in the box 1disposed in the housing 22 of the box bottom 2. As can best be seen inFIG. 14--respectively one end of a push rod 324a, 324b is linked to thetop of the pivot disk 25 via respectively a joint 312a, 312b, the otherends of which are connected via a respectively other joint 310a, 310bwith locking elements 321a, 321b. Each locking element 321a and 321b hastwo sliders 331a, 331b, which are displaceably guided in respectivelyone guide element 331a', 331b' parallel with the underside 23 of the boxbottom 2 and are coupled via yokes 332a, 332b. Respectively one bar333a, 333b rotatably seated in a pivot point 334 is connected via afurther joint 335 with the ends outside of the box of the sliders 331a,331b.

If the pivot disk 25 is pivoted in the direction of the arrow P, thepush rods 324a, 324b move their associated locking element 321a, 321btoward the outside, as a result of which the beak-like shaped bars 333a,333b are forced to make a rotating movement around their pivot point334. In the process, the beak-shaped ends 333a', 333b' of the bars 333a,333b extend out of the housing 22 of the box bottom 2--as best seen inFIG. 15--and dip into the locking slots 11a, 11b of the box 1, which aredisposed in the lower area 10 of the box 1 resting against the lateralsurfaces 2' of the box bottom 2. A secure locking of the box bottom 2 inthe box 1 is again achieved by this measure.

It has again been provided in an advantageous manner in the course ofthe pivot movement of the pivot disk 25 that the push rods 324a, 324bare moved beyond dead center of the joints 312a, 312b. At the end oftheir movement the push rods 324a, 324b embodied as toggle levers snappast their dead center and in this way lock in an advantageous manneragainst automatic opening. Because of this toggle lever effect by meansof the push rods 324a, 324b occurring in the course of the lockingmovement of the bars 333a, 333b, a particularly strong force effect onthe seal 214 of the box bottom 2 is again achieved, because of which itis pushed particularly strongly against the box 1. The extremely highlocking force between the box 1 and the box bottom 2 generated by thistoggle lever effect creates a perfect seal. The cassette 101 with thesubstrates 102 contained therein, which is received in the chamberhermetically closed by the box 1 and the box bottom 2, can therefore betransported without danger through a contaminated environment.

The second exemplary embodiment also differs from the first exemplaryembodiment by the type of drive for the turntable 45 of the detentmechanism which fixes the box 1 together with the inserted box bottom 2in place in the receiving frame 3. Reference is made in connection withthis to FIGS. 16 and 17, in which the alternative embodiment of thedetent mechanism of the first exemplary embodiment described in FIG. 9is illustrated: a cam plate 143 corresponding to the cam plate 43 ofFIG. 9 is now operated by means of the combined worm wheel--spur wheelgear. The cam plate 143, fixedly connected with the turntable 45, isembodied as a spur wheel which is engaged by a pinion 149. The pinion149 and a worm wheel 147 fixedly connected with it are seated on a shaft148 extending perpendicularly in respect to the underside 2' of the boxbottom 2. A worm 144 is disposed perpendicularly to this on the motorshaft 141' of a gear motor 141. In this case the gear motor 141 and itsmotor shaft are seated on two cheeks 142 and 143.

The described arrangement of this common drive device for the detent andthe locking mechanism has the advantage that because of this the gearmotor 141 can be installed horizontally in the lock gate 4, by means ofwhich it is possible in a particularly simple way to achieve theircompact construction.

I claim:
 1. A system for transferring substrates into a clean room,comprising:a box for receiving a cassette containing substrates, saidbox including a plurality of locking slots; a box bottom whichhermetically seals the box and which can be locked into and unlockedfrom said box; a receiving frame for receiving said box adjacent saidbox bottom and orienting said box relative to the clean room; a lockingmechanism for locking said box bottom to said box, said lockingmechanism including a pivot disk rotatably mounted in said box bottom,said pivot disk having a plurality of engagement bores, a plurality ofpush rods and an equal plurality of locking elements displaced by saidpivot disk via respective ones of said push rods to engage a respectiveone of said locking slots; a lock gate connected to said receivingframe, said lock gate having a turntable mounted therein, said turntablehaving a plurality of locking pins which engage respective ones of saidengagement bores of said pivot disk thereby connecting said turntable tosaid pivot disk; and a detent mechanism for fixing in place said box insaid receiving frame, wherein driving of said turntable by an operatingdevice of the system causes pivotal movement of said turntable whichtriggers locking of said box bottom in said box causing termination ofsaid fixing in place of said box in said receiving frame, and whichtriggers unlocking of said box bottom in said box causing fixing inplace of said box in said receiving frame.
 2. The system as defined inclaim 1, wherein said box further has a plurality of shoulders and saidreceiving frame receives a plurality of detent elements, equal in numberto said plurality of shoulders, wherein said detent mechanism includessaid plurality of detent elements, a cam-plate, a plurality of pushrods, each having a guide bolt extending therefrom, and a plurality ofcontrol cams connected to said cam plate, with a respective one of theguide bolts extending from said push rods being guided by a respectiveone of said control cams, and wherein the rotary motion of saidturntable is translated into a pivotal movement of said detent elementsacting on a respective one of said shoulders.
 3. The system as definedin claim 2, wherein said receiving frame includes a plurality ofcutouts, wherein said detent mechanism includes a plurality of bolts,one end of which defines one of said plurality of detent elements andthe other end of which define a pivot lever on which a respective one ofsaid plurality of further push rods acts, and a pivot spring coaxially,operatively associated with each bolt, with one end of each spring beingconnected with its respective bolt and its other end being supported bysaid receiving frame, and wherein with retraction of one of saidplurality of further push rods, the associated detent element is pivotedby the force of its associated spring out of its associated cutout andinto its detent position.
 4. The system as defined in claim 2, whereinsaid box bottom includes a plurality of runners, each connected to arespective one of said locking elements, wherein each control cam has afirst area defining a constant radius and a following second area inwhich the radius is defined to increase in such a way that passage ofits respective guide bolt therethrough leads to a displacement movementwhich cooperates with a respective runner to limit the lineardisplacement movement of the associated locking element, triggered by anassociated push rod, in the direction of an associated locking slot, andthat with further movement of the associated push rod in thedisplacement direction the associated locking element is tilted.
 5. Thesystem as defined in claim 4, wherein said push rods are embodied astoggle levers.
 6. The system as defined in claim 1, wherein said lockingmechanism further includes a plurality of rotatably seated bars eachdefining a pivot point and a plurality of guide elements, and whereineach locking element has at least one slider which is displaceablyguided in one of said plurality of guide elements, each slider beinglinked to one of said plurality of rotatably seated bars, said barsserving to translate the linear displacement movement of its associatedlocking element, in the direction of the associated locking slot, into arotating movement around said pivot point of said bar, by means of whichsaid box bottom is locked in said box.
 7. The system as defined in claim6, wherein the end of each bar is beak-shaped.
 8. The system as definedin claim 1, wherein each push rod in its connection to said pivot diskdefines a joint, and wherein each push rod can be moved beyond deadcenter of its defined joint in the course of their movement causinglocking of said box bottom in said box.
 9. The system as defined inclaim 1, further comprising:a ventilating device for the clean room,said ventilating device supplying a clean air flow to the clean roomwhich flows around the substrates, and including means for removing theair flow from the clean room after it flows around the substrates. 10.The system as defined in claim 9, wherein said means for removing theair flow from the clean room comprises a ventilating unit integratedinto the clean room.
 11. The system as defined in claim 9, wherein saidventilating device includes a grid element in the clean room forsteadying the clean air flow flowing through the clean room.
 12. Thesystem as defined in claim 9, wherein said ventilating device directsthe clean air flow parallel to the surface of the substrate around whichit flows.
 13. The system as defined in claim 9, further comprising:alifting device integrated into the clean room for said lock gate, andwherein the clean air flow is guided to said lifting device after itpasses around the substrates.
 14. The system as defined in claim 13,wherein said ventilating device includes a grid element in the cleanroom for steadying the clean air flow flowing through the clean room,and wherein said grid element is disposed ahead of said lifting devicein the direction of clean air flow.
 15. The system as defined in claim13, wherein said lifting device includes a carriage, a driven threadedspindle and a support arm, said driven threaded spindle serving to liftsaid support arm which acts on said lock gate.
 16. The system as definedin claim 1, further comprising:a substrate fixing device disposed insaid box.
 17. The system as defined in claim 16, wherein said substratefixing device includes a scissors brace and a pressure strip connectedwith the scissors brace, and wherein said scissors brace cooperates withsaid box bottom by means of which a lifting movement of said box bottomis translated into a pressing movement by said pressure strip againstthe substrates in the cassette.
 18. The system as defined in claim 1,further comprising:an operating device which drives said lockingmechanism and said detent mechanism, and wherein said operating deviceis completely disposed within said lock gate.
 19. The system as definedin claim 18, wherein said operating device includes a bracket hinged tosaid lock gate, a motor with a gear received within said bracket, athreaded spindle, and a fork having a counter-screw thread, said forkbeing hinged to said cam plate, and wherein said threaded spindle isflanged to a shaft of said motor and meshes with the counter-screwthread of said fork.
 20. The system as defined in claim 18, wherein saidoperating device includes a pinion in engagement with said cam plateformed as a spur wheel, a worm wheel fixedly connected with said pinion,a gear motor having a motor shaft, and a worm connected to said motorshaft and flanged to engage with said worm wheel.
 21. The system asdefined in claim 1, wherein said box bottom includes a housing, aplurality of runners, each connected to a respective one of said lockingelements, and a plurality of stops equal in number to the plurality ofrunners, wherein at least one of said runners slides on the underside ofsaid housing and engages, as a limit, a respective one of said stops,said movement of said runners toward its respective stop being triggeredby its associated push rod moving in the direction of its associatedlocking slot, with further movement of said push rod in the direction ofits associated locking slot causing its associated locking element totilt.
 22. An SMIF-system for transferring substrates into the lock of aclean room with a box for receiving a cassette containing thesubstrates, comprising:a ventilating device provided in the clean roomfor supplying an air flow to the clean room which flows around thesubstrates, wherein the clean room has an inlet opening and an exhaustopening, said ventilating device having a ventilating unit disposed onthe exhaust opening side of the clean room for removing the clean airflow flowing through the clean room and for generating a displacementflow which is caused by a pressure gradient between the clean air flowflowing through said inlet opening from an adjoining further clean roomand the flow at said exhaust opening.
 23. The system as defined in claim22, further comprising:a lifting device integrated into the clean room,and wherein said ventilating device includes a grid element in the cleanroom for steadying the clean air flow flowing through the clean air roomand for screening said lifting device.
 24. The system as defined inclaim 23, wherein said ventilating device directs the clean air flowparallel to the surface of the substrate around which it flows.
 25. Thesystem as defined in claim 22, further comprising:a lifting deviceintegrated into the clean room, and wherein the clean air flow is guidedto said lifting device after it passes around the substrates.
 26. Thesystem as defined in claim 25, wherein said ventilating device includesa grid element in the clean room for steadying the clean air flowthrough the clean room, and wherein said grid element is disposed aheadof said lifting device in the direction of clean air flow.